Process for preparing iodoarene compounds

Abstract

Diacetoxyatene compounds are obtained by reacting a perborate such as sodium perborate monohydrate or tetrahydrate and acetic acid with an iodoarene compound under mild conditions, such as 40 to 50° C. The iodoarene can be further substituted by a wide range of substituents, such as halo, nitro, alkyl, alkoxy or carbosylic acid, in any position around the nucleus, except that electron withdrawing substituents occupy meta positions only. The invention process thus enables a wide range of substituted diacetoxyarene compounds to be produced using widely available and easily handled materials under mild operating conditions.

We claim: 
     
       1. A process for the preparation of a diacetoxyiodoarene compound by reaction between an iodoarene compound and a donor of acetoxy groups in the presence of an oxidising agent, wherein an unsubstituted or substituted iodoarene compound is brought into contact with an excess of alkali metal perborate and acetic acid at a mild temperature and permitted to react until at least a proportion of the iodoarene has been oxidised to the corresponding diacetoxyiodoarene, provided that any electron-withdrawing substituent is meta to the iodo substituent. 
     
     
       2. A process according to claim 1 wherein the iodoarene compound comprises an iodo substituted benzene or di or polycyclic arene nucleus that is further substituted by 0 to 4 additional substituents. 
     
     
       3. A process according to claim 1 or 2 wherein the iodoarene compound is substituted by at least 1 substituent selected from the group consisting of halo, nitro, carbosylic acid, nitrile, alkyl and alkoxy groups. 
     
     
       4. A process according to claim 1 or 2 wherein the alkali metal perborate is selected from the group consisting of sodium perborate monohydrate and tetrahydrate. 
     
     
       5. A process according to claim 1 or 2 wherein an alkali metal perborate is employed in a mole ratio to the iodoarene of from 5:1 to 15:1. 
     
     
       6. A process according to claim 1 or 2 which the reaction temperature is in the range of from 35° to 70° C. 
     
     
       7. A process according to claim 1 or 2 which the reaction period is in the range of 3 to 12 hours. 
     
     
       8. A process according to claim 1, wherein an iodoarene compound substituted by at least one substituent selected from the group consisting of halo, nitro, carboxylic acid, nitrile, alkyl, and alkoxy groups is brought into contact with sodium perborate monohydrate or tetrahydrate in a mole ratio of perborate to iodoarene of from 5:1 to 15:1.